Vehicles today are increasingly being equipped with a particle filter to filter exhaust gases from their engines. These filters can be regenerated at suitable intervals of time, which involves raising the temperature of the vehicle's exhaust gases by dosing a combustible substance to the exhaust system upstream of the filter. Said temperature raising takes place when the combustible substance burns.
The time required for a regeneration procedure may for example be 30-60 minutes, during which it is therefore desirable that the temperature of the exhaust gases be above a lowest necessary temperature.
When a vehicle provided with a two-pedal system, a power train with automatic gearbox and torque converter is stationary, certain vehicle brakes may be applied when the vehicle is in what is usually called a “drive” state which the driver has put the vehicle's control system into by means of a mode selector. The braking action of the brakes may prevent the vehicle from moving off. To keep the vehicle stationary, the braking action needs to be greater than the propulsive force imparted to the vehicle's tractive wheels by torque transmitted from the engine.
In a typical application, e.g. in buses, so-called stopping-place brakes are activated where the vehicle comes temporarily to a halt at stopping places along a certain route. During a regeneration of the particle filter, the power train will nevertheless transmit a certain torque to the vehicle's tractive wheels, since a certain load upon the engine is needed to maintain the temperature of the vehicle's exhaust gases. Regenerating the particle filter when the vehicle is stationary thus entails certain traffic safety risks.
US 2009/019838 describes a method for raising an exhaust temperature by increasing the load upon the vehicle's engine during regeneration of a particle filter. The output shaft from the vehicle's gearbox may be locked while at the same time a torque converter is operating.
US 2004044457 describes a method for regeneration of a particle filter of a vehicle.